Land law help me!!!!

If there are 5 people (A,B,C,D&E) who are living as joint tenants, then one of them (A) decides to sell to someone else (a third party 'X') that severs the Joint tenancy and becomes a Tenancy in common because that new person ('X') will only have the unity of possession. Also seeing as joint tenancy's cannot be severed at law the original person (A) will still have legal interest just they sold their beneficial interest. Am I right? Also because A severed the joint tenancy into a tenancy In common, are the remaining people (B,C,D&E) joint tenants or tenants in common?

At least make a start on this. We can't and won't do this homework for you.

Thank you. I did find the video helpful in understanding that the remaining tenants are Joint tenants whereas the individual who severed is a TiC. So in the scenario I gave above, A will remain as legal ownership but X will have taken his place as equitable? Therefore were the house to be sold the monies would go to X? And A gets nothing? Excpet he has to be notified of the selling I suppose...??? Sorry I’m very confused on the matter and have watched a number of videos and read textbooks on it..